Vibration actuator

Abstract

A vibration actuator excites a mass member by interaction between an electric field of a vibration coil provided in an inner space of a case and a magnetic field of a magnetic field unit disposed corresponding to the vibration coil. The vibration actuator has an elastic wire having a wire body fixed to the outer surface of the mass member and elastic ends fixed to the inner surface of the case. The elastic wire is connected between the case and the mass member for elastically supporting mass member.

1. A vibration actuator for a mobile communications device, for exciting a mass member by interaction between an electric field of a vibration coil provided in an inner space of a case and a magnetic field of a magnetic field unit disposed corresponding to the vibration coil, wherein the vibration actuator comprises:
 an elastic wire having a wire body fixed to the outer surface of the mass member and elastic ends fixed to the inner surface of the case, the elastic wire being connected between the case and the mass member for elastically supporting the mass member; 
 wherein the mass member has a disposition groove formed, in a helical shape having at least one turn, at the outer surface thereof. 
 
   
   
     2. The actuator as set forth in  claim 1 , wherein the elastic wire is composed of a coil spring comprising a coil body disposed in the disposition groove and elastic ends fixed to the inner surface of the case. 
   
   
     3. The actuator as set forth in  claim 1 , wherein the wire body of the elastic wire is wound around the disposition groove of the mass member. 
   
   
     4. The actuator as set forth in  claim 1 , wherein the wire body of the elastic wire is forcibly fitted in the disposition groove of the mass member. 
   
   
     5. The actuator as set forth in  claim 1 , wherein the mass member comprises:
 at least two mass disks having different diameters, the at least two mass disks being stacked on each other with an end face of one of the mass disks facing another end face of the other mass disk; and 
 wherein the disposition groove is provided between the at least two mass disks and the wire body of the elastic wire is disposed in the disposition groove. 
 
   
   
     6. A vibration actuator for a mobile communications device, for exciting a mass member by interaction between an electric field of a vibration coil provided in an inner space of a case and a magnetic field of a magnetic field unit disposed corresponding to the vibration coil, wherein the vibration actuator comprises:
 an elastic wire having a wire body fixed to the outer surface of the mass member and elastic ends fixed to the inner surface of the case, the elastic wire being connected between the case and the mass member for elastically supporting the mass member; 
 wherein the mass member comprises: 
 a hollow outer mass part having
 a disposition groove formed, in a helical shape having at least one turn, at the outer surface of said hollow outer mass part, and 
 a center hole formed through the center of said hollow outer mass part, the center hole having a predetermined size; and 
 
 an inner mass part inserted in the center hole. 
 
   
   
     7. A vibration actuator for a mobile communications device, for exciting a mass member by interaction between an electric field of a vibration coil provided in an inner space of a case and a magnetic field of a magnetic field unit disposed corresponding to the vibration coil, wherein the vibration actuator comprises:
 an elastic wire having a wire body fixed to the outer surface of the mass member and elastic ends fixed to the inner surface of the case, the elastic wire being connected between the case and the mass member for elastically supporting the mass member; 
 wherein the mass member is made of a resin material having a disposition groove formed by molding. 
 
   
   
     8. The actuator as set forth in  claim 1 , wherein the magnetic field unit comprises:
 a yoke fixed to the mass member; and 
 a magnet mounted in the yoke. 
 
   
   
     9. The actuator as set forth in  claim 8 , wherein the magnetic field unit further comprises:
 an upper plate disposed on the upper surface of the magnet. 
 
   
   
     10. The actuator as set forth in  claim 1 , further comprising:
 a shield plate for closing an opened lower part of the case, the vibration coil being disposed on the upper surface of the shield plate. 
 
   
   
     11. The actuator as set forth in  claim 1 , further comprising:
 a voice coil disposed at an opened upper part of the case for generating an electric field when an electric current is supplied to the voice coil; and 
 a diaphragm attached to the lower surface of the voice coil. 
 
   
   
     12. The actuator as set forth in  claim 1 , wherein the mass member comprises:
 a hollow outer mass part having the disposition groove formed at the outer surface thereof, and a center hole formed through the center thereof, the center hole having a predetermined size; and 
 an inner mass part inserted in the center hole. 
 
   
   
     13. The actuator as set forth in  claim 1 , wherein the mass member is made of a resin material having the disposition groove formed by molding.